I am a beginner at Tensorflow Neural Networks, and I am following an online guide to learn how to train Sequential Neural Network models. When computing the mean squared error of my test data, I get very different results every time I compile the model. Sometimes I get a MSE of about 27 to 28, and other times I get a very strange MSE of ~20,000. I am not changing any variables every time I recompile my model. Why is this happening? Thanks for responding.